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FIELD COLUMBIAN MUSEUM. 

PUBLICATION No. 127. 
ZOOLOGICAL SERIES. VOL. VII, No. 6. 



THE ZOOLOGY OF LAKES 
AMATITLAN AND ATITLAN, 

GUATEMALA, WITH 

SPECIAL REFERENCE TO 

ICHTHYOLOGY 



BY 



SETH EUGENE MEEK, 
Assistant Curator of Department. 



CHARLES B. CORY, 
Curator of Department of Zoology. 




CHICAGO, U. S. A. 

April, 1908. 



The Zoology of Lakes Amatitlan and Atitlan, Guatemala, 
with Special Reference to Ichthyology. 



By SETH EUGENE MEEK. 



The following paper is the result of a study, under the patronage of 
the Government of Guatemala, of Lakes Amatitlan and Atitlan for 
the purpose of determining whether and how the quantity and quality 
of the useful food and game fishes of these lakes could be increased, 
and to determine the suitability of the waters for the introduction 
of species of food-fishes from the United States and elsewhere, and 
the possibilities of fish-cultural operations. This investigation was 
undertaken at the request of His Excellency, Sefior Don Manuel 
Estrada Cabrera, President of the Republic of Guatemala. Most 
attention was given to Lake Amatitlan, which is only twenty miles 
from the City of Guatemala, and easily accessible to the residents of 
that city. The field work was done during the months of January 
and February, 1906. In this I received considerable assistance from 
Dr. Kellerman and Mr. Smith, of the Ohio State University, who 
were in Guatemala at this time collecting plants, and from Dr. N. 
Dearborn and Mr. C. M. Barber, who were then in Guatemala col- 
lecting birds and mammals for this Museum. For notes and other 
aids concerning the plants of this region, I am indebted to Miss 
Josephine E. Tilden,* of the University of Minnesota, Dr. J. M. Green- 
man, of this Museum, and Mr. H. W. Clark,f of the U. S. Bureau of 
Fisheries. 

In the study of the collections of animals made during this time, 
I received the assistance of specialists to whom credit is given in the 
accounts of the groups studied by each. I also received many cour- 
tesies from Dr. B. W. Evermann, in charge of the Division of Scientific 
Enquiry of the U. S. Bureau of Fisheries. Mr. J. W. Titcomb, in charge 
of the Division of Fish Culture U. S. Bureau of Fisheries, kindly 
assisted me in that portion of this paper relating to the recommenda- 
tions of the most suitable fishes from the United States for introduc- 
tion into these lakes. I wish to acknowledge my indebtedness to 
Mr. Combs, U. S. Minister to Guatemala, his secretary, Mr. Brown, 



* Proc. Biol. Soc. Wash. 1908, 106-110. 
t Proc. Biol. Soc Wash. 1908, 92-105. 



159 



i6o 



FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 



and to Mr. Winslow, U. S. Consul General, for many courtesies; also 
to Mr. Hodgson and Mr. Tisdal, of the Guatemala Central Railroad, 
who very materially aided me in transportation. I am especially 
indebted to Mr. Carlos Palma, of the Consulate of Cuba, who very 
greatly aided me in my business relations with the Government 
Officials of Guatemala. 

It is, perhaps, not out of place here to state that this investigation 
grew out of a desire of President Cabrera to do something to increase 
the value of the food supply of Lake Amatitlan. He therefore asked 
Hon. George M. Bowers, U. S. Commissioner of Fish and Fisheries, to 
recommend some person who was properly trained to make the neces- 
sary preliminary investigation, to insure the best possible results. 

Very little has been done towards the study of the Zoology of 
tropical lakes, which makes the study of these bodies of water of 
some scientific value. The Government of Guatemala has already 
begun to establish a Fish Cultural station on Lake Amatitlan, the 
results of which will be watched with considerable interest. 

It might also be well to note here that no attempt was made to 
collect and study the insects in or about the lake. The species of 
insects most important in an investigation of this kind are those forms 
whose larvae live for a time in the water. During the winter, or dry 
season, these insects are less active than in the summer, or wet season. 




VOLCAN DE AGUA FROM LAKE AMATITLAN 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 



161 



LAKE AMATITLAN. 

Lake Amatitlan is situated on the Pacific slope of Guatemala in 
lat. 90 30' N., long. 14 25' W. Its surface is about 4,000 feet above 
sea level, and about 1,000 feet below the plateau on which the City of 
Guatemala is built. It is strictly a mountain lake, the depression 
which it occupies having been formed when the surrounding mountains 
took their present form. It may, therefore, best be considered as 




HOTEL LAGUNA, LAKE AMATITLAN 

occupying the bottom of a depression in the plateau above mentioned. 
The lake and its small valley are surrounded by mountains whose 
average altitude, except the canon and a few low hills to the south- 
west, is from about 800 to 1,300 feet above its surface. It occupies 
an area near the head waters of the Michatoya River, through which 
its waters find an outlet to the sea. During the earliest portion of 
its history it was somewhat oval in outline, its greatest width being 
about 3 miles, its length about 8 miles. The long diameter of the 
lake is nearly in a northwest and southeast direction. To the north- 
east is a small valley which is drained into the lake by the Lobos 
River, the only stream which flows into the lake during the entire 
year. This stream has the appearance of having shifted its position 



l62 



FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 



many times during the past centuries, and to have been responsible 
for transporting much of the material which has filled up about two- 
fifths of the lake. The material worn from the mountains by rain has 
been transported by the inlet and other small streams to the lake, form- 
ing that portion of the low land bordering it to the north and east. 




LAKE AMATITLAN FROM ITS UPPER END 

This land has so encroached on the lake that now it is narrowest near its 
middle, where it is only one-fourth of a mile wide. The bottom at this 
place is of soft mud, apparently to a considerable depth. This is evi- 
dent from the fact that much trouble was experienced in making a fill 
across this narrow portion for the railroad. This fill sank out of 
sight as soon as the soft material of which the bottom of the lake is 
composed became overloaded. It required much more material to 
make the railroad fill than the depth of the water indicated. 

To the northwest, the mountains consist of hard granite rock and 
basaltic columns. The other mountains about the lake are mostly 
composed of loose material, much of it being volcanic ashes, pumice, 
and other soft material, which is easily eroded. The hills which border 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 163 




SHORE NEAR OUTLET OF LAKE AMATITLAN 




DELTA AT MOUTH OF LOBOS RIVER LAKE AMATITLAN 



164 



FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 



the valley to the north are composed mostly of this softer material. 
Even now, in low water, the Lobos River, which drains this valley, 
rolls along on its bottom a considerable amount of this material, form- 
ing at its mouth a small though quite typical delta. The valley 
about and above Moran shows evidence of considerable erosion, and 
the material carried away forms a large portion of the low land below 
this city. 

Lake Amatitlan is about 8 miles long, and about 2% miles wide 
at either end, and % mile near its middle. The fill on which the rail- 




DELTA AT MOUTH OF LOBOS RIVER, LAKE AMATITLAN 

road is built divides the lake into two parts, or two quite similar 
basins. The upper is the smaller, and near its center is 95 feet in 
depth. The lower and larger portion is no feet deep. In its nar- 
rowest portion, both above and below the railroad, the lake is 50 feet 
deep. 

The bottom of the lake is a quite uniform basin ; the lake is deepest 
where widest, and the slope from shore line to bottom is everywhere 
steep and quite uniform. The bottom is covered with a light mud, 
mixed with the remains of small plant life. At a depth of about three 
feet this mud becomes somewhat firm, and is a clay-like substance of a 
grayish-blue color. The bottom at the base of the tules is quite firm, 
being covered with a light mud, sand, and gravel. 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 



165 




i66 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

The temperature of the water in the lake is very uniform. During 
the time of these investigations, the surface temperature varied from 
70 F. at 6:30 A. M. during the last few days in January, to 76 F. at 
noon to 4 p. M. about the middle of January. The heat of the sun 
during the day does not warm the water at the surface to a depth of 
more than 5 to 10 feet, while during the night it cools off quite 
rapidly. From January 22 to February i, the temperature of the 
air at 6:30 A. M. was from 53 F. to 60 F., while during the day it 
seldom rose to 70 F. These ten days of cool weather did not cool 




HOT SPRING, LAGUNA, LAKE AMATITLAN 

the water in the lake more than one or two degrees. From my obser- 
vation it is quite evident that the water in the lake never becomes 
cooler than 69 F., and that it is never, except near the surface, more 
than two or three degrees warmer than this. These temperatures 
were taken with a Nigretti-Zamba deep-sea thermometer. The bottom 
temperatures taken were not always recorded, for all of these taken 
at the bottom on any one day were the same. 

Along the south and east ends of the lake are a number of warm 
or hot springs. These springs discharge their waters into the lake 
at its surface, where it forms only a thin layer of hot water over a 
small area near the spring, and soon becomes the same temperature as 
the air. The hot springs influence the temperature of the water in the 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 167 

lake only a few feet from the shore, and then only at the surface. The 
many bottom temperatures which I took in all parts of the lake did 
not indicate any local sources of heat in the bed of the lake. I was 
unable to secure a thermometer in the City of Guatemala which would 
register over 110 F. and so I was unable to take the temperature of 
the water as it came from these hot springs. The largest and hottest 
one, near the station of Laguna, was hot enough to boil eggs very suc- 
cessfully. In 6 minutes the egg would be soft boiled, at 10 to 12 
minutes medium, and at 15 minutes the yolk would be hard but the 
white was quite soft. 

The small fishes (Pcecilia sphenops} will swim nearly up to these 
springs, but they remain in the cooler layer of water near the bottom. 
They appear to be swimming in water hot enough to scald one's hand, 
but in reality are in water not warmer than 90 or 100 F. A few of 
these fishes were placed by me in water taken directly from the spring, 
and these died almost immediately. These small fishes, although they 
come very close to the spring, do so in the lower stratum of water. 
The hot springs on the margin of Lake Amatitlan are too small and 
too near the surface to have any influence on the general temperature 
of the water in the lake. 

The water is only moderately clear. A white disc 12 inches in 
diameter cannot be seen at a depth of over 10 to 15 feet, seldom over 
12 feet. The same disc is plainly visible in Atitlan at a depth of 
45 feet. The lack of clearness is due more to the abundance of Plankton 
(microscopic animals and plants) in the water than to the fine, silt-like 
material held in suspension. The water in Lake Amatitlan is slightly 
alkaline, having a specific gravity of about 1.002 (specific gravity of 
sea water is 1.027). Compared with water from Lake Michigan, it 
contains relatively larger quantities of soda, potash, lime, magnesia, 
soluble silica, and chlorine. It also contains a small quantity of iron 
and aluminum. The following table gives a comparison of the more 
common mineral substances as found in Lake Amatitlan and Lake 
Michigan. The analysis of the water from Lake Michigan was made 
in office of Chicago Board of Health; that of Lake Amatitlan by Mr. 
R. Gwirz, in charge of the Government Chemical Laboratory of 



i68 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

Guatemala. From these analyses, the following table was prepared 
by Mr. Nichols, of this Museum: 

Parts per million. 
L. Michigan. L. Amatitlan. 

Silica 5 .00 40 .00 

Calcium Carbonate 50 .00 140 .00 

Magnesium Carbonate 16 .68 27 .30 

Calcium Sulphate 22.77 trace 

Sod. & Pot. Chloride r 4-75 210.00 

Sod. & Pot. Carbonates . 2.24 .... 

Ferric Oxide & Alumina trace 6 . oo 

Phosphates trace 

Potassium Nitrate 2 .00 

Nitrates none 

Ammonia .02 

Oxygen consumed 

in acid sol 4.6 

in alkaline sol 4.6 

Total solids 1 1 1 . 40 42 1 . oo 

It will be noticed that the total solids in the water of Lake Ama-- 
titlan is nearly four times that of Lake Michigan, although but about 
i . 2 per cent of that of sea water. The water of Lake Amatitlan, 
though considerably used by the residents for drinking purposes, is 
not a good potable water. It is slightly salty to the taste, and its 
oxygen consuming power indicates the presence of considerable de- 
composing organic matter, and consequently the probable presence of 
bacteria. It is probable that this test of the water was made some 
time after the water was taken from the lake, and is not a fair indica- 
tion of its actual condition. By the residents of this region the lake 
water is regarded as poor for drinking purposes. 

The amount of mineral matter in the lake is too small to unfit the 
water for fresh water fish life. The volume of water is large, and the 
inflow and the outflow great enough to prevent the lake water from 
ever becoming salty to any harmful extent. 

The shore vegetation of the lake may be characterized as only 
moderately abundant. A few large trees, as the Willow (Salix 
Humboldtiana), and several species belonging to the genus Ficus 
(Rubber-trees) grow close to the water's edge, their low, drooping 
branches being often bathed by the waves. These trees afford a con- 
siderable amount of shade, which appears to be a favored hiding place 
for fishes in the lake. This, and other land vegetation, supports a 
large number of Fungi and Epiphytes (Orchids and Bromeliads) attrac- 
tive to insects, which are constantly falling into the lake and forming a 
supply of food for fishes. There are no extensive forest areas on the 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 169 




WILLOWS ON UPPER PORTION OF DELTA, LAKE AMATITLAN 




UPPER END OF LAKE AMATITLAN 



170 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

sides of the mountains immediately bordering the lake. The low 
flat area to the north and east is under cultivation. On it are grown 
sugar cane, lemons, oranges, and various other tropical fruits. The 
shrubs which grow close to the water's edge belong mostly to the 
Compositae, and with these are usually associated many species of 
Lichens, Mosses, Hepatics, Ferns, and the like. 

The flowering plants of the marshes are only moderately abundant 
along the shores of Lake Amatitlan, for there is very little low wet 
land along the margins, and very small areas of shallow water. The 
sudden great depth makes it quite impossible for the higher aquatic 
plants, particularly the marsh plants, to secure a foothold. 

The most conspicuous of these marsh plants is a species of Cat-tail 
(Typha angustifolia) , and a tall Rush (Scirpus sp.). These two species 
are recognized as Tules by the natives, who cut and dry them for 
weaving into mats. They usually grow together, and when this occurs 
one is generally much more abundant than the other. The Rush is 
the more abundant of the two in the deeper water. Neither of these 
grows where the water is more than five or six feet in depth, more than 
half of the plant being above the water. A small Spike Rush (Eleo- 
charis sp.) is quite abundant along the shore next the lowland where 
sandy. It grows to a height of from one to eight inches, and is usually 
entirely submerged. It is at the base of these Cat-tails and Rushes 
that the larger Moj arras find their best breeding and spawning 
grounds, and where the fishermen find the capture of these fishes the 
easiest. 

There are two species of grasses growing in patches along the shore 
of the lake. The larger one (Panicum sp.) is more common on the 
south side of the lake, more particularly where the margin is rocky. 
In general appearance it resembles sugar cane more than it does any 
other plant growing in the water of the lake, the other grass (Phrag- 
mites sp.) is widely distributed here, but is nowhere abundant. It 
occurs mostly on the side adjacent to the lowlands. 

There are two floating plants which occur on the lake ; the smaller 
(Salvinia natans) is the more widely distributed, being found in most 
places where there is other vegetation, and especially so in the neigh- 
borhood of warm springs. The larger of these floating plants is the 
Water Lettuce (Pistia obcordata), not found except along the shore 
next the low lands. It is abundant at only one plant, about one half 
mile above the railroad. The inhabitants call this plant La Chuga. 
It is easily distinguished from all other floating plants by its broad 
leaves growing in the form of rosettes. 

There are several species of Pickerel weeds growing in the shallow 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 171 

water where they can get a foothold. In most places, especially next the 
low lands, these plants are very abundant, usually growing to a depth 
of 20 feet or more. They are usually submerged, though occasionally 
the upper leaves or those in the shallow water float on the surface. 
Two species of these (Potamogeton lucens and Potamogeton sp.) are 
very abundant where found. Associated with these is a Hornwort 
(Ceratophyllum demersum) , and two or three species of Char a are abun- 
dant. These submerged plants are very important in connection with 
fish food supply, since the absence of such plants means absence of the 




WILD LETTUCE, LAKE AMATITLAN 

small animals and insect larvae, as well as a decrease in the quantity 
of algae. The tender portions of these plants furnish a considerable 
supply of food for the smaller fishes in the lake. 

There is in Lake Amatitlan a considerable quantity of microscopic 
organism, or Plankton, enough to prevent the water from being suffi- 
ciently clear to see a white object a foot in diameter deeper than 12 or 
15 feet. The Phytoplankton here much exceeds the Zooplankton; 
in Lake Atitlan the reverse is true. In general the Zooplankton is 
dependent on Phytoplankton for its food supply. The Phytoplankton 
of Lake Amatitlan consists chiefly of algae. Closely allied to but not 
properly included in Plankton are the larger forms of filamentous 
algae. These are usually associated with the marsh plants and are often 



172 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

attached to rocks, pieces of dead timber, sticks, and to the branches of 
trees which touch the water. The non-filamentous forms, or the blue- 
green slimes, are very abundant, and with many of these are associated 
filamentous forms. Some species grow in considerable quantities in 
very warm water near the warm springs. The most conspicuous and 
by far the most abundant of these blue-green forms is a species of 
Clathrocystis. It is exceedingly abundant near the surface in the upper 
half of the lake, or rather that portion above the railroad, but is not 
noticeable to the naked eye on that portion of the lake below the 
railroad. Associated with this form, in colonies, are several species 
of Anacystis and Anab&na. Belonging to these genera are the char- 
acteristic " Wasserbliite " plants, but these nowhere on the lake or 
near its margins formed a scum on the surface, and so, in the strict 
sense, "Wasserbliite" cannot be said to exist on the lake in January 
and February, especially so on its lower half; although, in a broader 
use of the term, the presence of Anabcena and Clathrocystis in such 
abundance indicated that it did exist to a limited extent, at least, on 
the upper half of the lake. " Wasserbliite " is considered by some 
writers to be injurious to fishes, especially so in small stagnant ponds. 
While this may be true in small ponds, it certainly is not in such large 
bodies of water as this lake, where the surface is frequently agitated. 
These forms do form a portion of the food supply of the fishes in 
this lake, and no doubt furnish the important food supply of Ento- 
mostraca. 

The fact that the water in Lake Amatitlan has about the same tem- 
perature during the entire year would indicate that Plankton was 
quite uniform in quantity at all times; a condition which is not true, 
however, of our northern lakes. 

In Lake Amatitlan the Phytoplankton is much more abundant in 
January and February than the Zooplankton. In Lake Atitlan the 
reverse is true. Lake Atitlan, the larger lake, is about 1,000 feet 
higher. Its water will average from one to two degrees cooler than 
Lake Amatitlan. It has no outlet, and its drainage area is very small. 
That portion of Lake Amatitlan which is the least disturbed by the 
inflow and the outflow of water contains by far the greatest abundance 
of Phytoplankton. 

The abundance of the blue-green algae previously mentioned on 
onte portion of lake, and not on the other, is not well understood. 
The only reason I am able to suggest why they are so much more 
abundant in the upper part of the lake than in the lower is that the 
drainage into this portion of the lake is small compared to that 
received by the lower portion. The upper part of the lake becomes 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 173 

to some extent a body of partially stagnant water. In the lower 
portion there is a constant flowing in of a considerable amount of 
water at its upper portion, and a constant outflow at the opposite 
end. This would tend to decrease the quantity of any floating parti- 
cles in the water. Much of the algae floats on or near the surface. 
It is often driven together by the wind, forming on the surface of the 
lake large, blue-green patches. The alga? to which these species are 
most nearly related form a large portion of the food supply for micro- 
scopic animal life, and for small fishes which feed on vegetation. The 
Algae and softer portions of the other water plants furnish a large part 
of the food supply for the young fishes, and also for the adult of the 
three most abundant species of fishes (Pescadito, Serica, and Mojarra) 
in the lake. 

The water of Lake Atitlan is very clear as compared with that of 
Lake Amatitlan and, as noted above, the amount of Plankton material 
in it is very much less. 

So far as I could discover there are no diseases among the fishes of 
Lake Amatitlan. The Mojarras are occasionally infested with intes- 
tinal parasites, but the fishes appear in good condition, which indicates 
that these do no harm. Parasites are occasionally noticed in the other 
species of fishes in the lake. Intestinal parasites are not uncommon 
with fishes and other animals, and their presence is not to be regarded 
as an indication of ill health or disease. In our northern waters there 
are occasionally epidemics among fishes during which many dead and 
dying are found along the shore. I was unable to learn of any similar 
epidemic among the fishes of Lake Amatitlan. If such ever occur 
they are not at all frequent or serious. During my stay at the lake all 
animal and plant life in the lake appeared vigorous and healthy. The 
uniform temperature of the water, the freedom from sewage, and the 
large volume of water, are all factors which induce a very healthful 
condition in this body of water. An over supply of plant life contri- 
butes largely to eliminate from the lake the noxious gases formed from 
any decomposition of animal or vegetable life, and to take up the 
waste products of water animals. 

The conditions of Lake Amatitlan, its fish food supply, the tem- 
perature and purity of its water, etc., are such that it should contain a 
far greater number of large fishes than it does at present. In general, 
the fishes which feed on animal life are superior as food for man to 
those whose food consists mostly or entirely of plants; and it is this 
class of the larger fishes that is lacking in the lake. The smaller 
fishes, especially the Pescadito, are very abundant, and it seems best 
to introduce a few large species into the lake which would utilize these 



174 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

for food. In this way a species of fish (the Serica), worthless as food 
for man, and another species (the Pescadito), too small to ever become 
a desirable food fish, could probably be converted into good food 
fishes. 

In the Pacific Slope rivers of Guatemala there are no Mojarras 
which strictly feed on small fishes, and none larger or better than the 
one now found in the lake. The largest one (Cichlasoma trimacu- 
latum) could easily be introduced into the lake. Its introduction 
would, to some extent, increase the food fish supply of the lake and 
its presence there would do no harm. 

In the Rio Montagua and in Lake Isabel is a large Mojarra (Cich- 
lasoma motaguense) which feeds mostly on small fishes. After the 
completion of the Guatemala Northern Railroad the introduction of 
this fish into the lake could be easily accomplished. It is a larger 
species than the Mojarra which now lives in the lake. 

The Robalo (Centropomus nigrescens] and the Pepemechin (Philyp- 
nus dormitor) are food fish of some value. These are both found in the 
Pacific Coast streams of Guatemala. Concerning the value of these 
fishes as food or game fishes I know almost nothing. The Pepemechin 
is quite common in the lakes of Nicaragua, and is sold in the markets 
there for about the same price as is the Mojarra. 

The Large-mouth Black Bass, which is found in all of the streams 
and lakes of the eastern United States, from Lake Superior to Tampico, 
Mexico, is a most excellent game and food fish. It feeds almost alto- 
gether on small fishes. Its flesh is firm and better flavored than that 
of any of the Mojarras or other fishes above mentioned. This fish is a 
great favorite with sportsmen, who fish with hook and line for pleasure. 
So highly prized is it in the United States, that it has been introduced 
into many of the western lakes and streams. The rate of growth of 
the Large-mouth Black Bass varies much in different localities. Indi- 
viduals in some of our United States hatching stations are known to 
reach a weight of two to eleven pounds when two or three years of age. 
In lakes and streams in the southern United States this fish is often 
taken weighing 6 or 8 pounds, while individuals are not uncommon 
weighing 20 pounds or more. It grows larger and grows more rapidly 
in the waters of our southern states than farther north. In these 
southern waters it feeds during most of the year. During the winters 
in the northern portion of the United States the lakes and rivers become 
covered with ice, and the water in them under the ice is so cold that 
fishes become inactive and do not eat. So there is a period of from 
2 to 4 months that fishes have no chance to grow. The water in 
Amatitlan is always warm enough to prevent this period of inactivity, 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 175 

and so fishes will grow larger in a given time there than in the United 
States. In this respect there is a marked difference in the growth of 
the Large-mouth Black Bass in the lakes of Wisconsin and of Florida. 
The Large-mouth Black Bass spawns in the spring. It deposits its 
eggs in shallow nests which it makes near the shore in shallow water. 
Its habits in this respect are about the same as those of the Mojarra 
found in Lake Amatitlan. 

Closely related to the Large-mouth Black Bass are the Rock Bass 
(Ambloplites rupestris), the Crappie (Pomoxis sparoides) , and the Blue- 
gill (Lepomis pallidus). These seldom exceed one or two pounds in 
weight. They feed on small fishes and afford much pleasure in their 
capture with hook and line. They are excellent food fishes. These 
fishes could easily be introduced with the Large-mouth Black Bass. 

In the lakes of Nicaragua is a species of Mojarra known as Guapote 
(Cichlasoma managuense) . In shape and form it much resembles the 
Large-mouth Black Bass of the United States. It grows to a length 
of 12 to 1 8 inches. This fish feeds upon smaller fishes. It is the best 
flavored food fish found in the lakes in Nicaragua. It will live out of 
water much longer than any of the fishes I have so far mentioned, 
which fact will greatly assist in its introduction into other waters than 
where found. Nothing is known of its spawning habits. Considering 
the temperature of the water (83 F.) in which it lives, its flesh is 
exceeding firm and well flavored. In the future stocking of tropical 
lakes with fishes, I am sure the Guapote should, and no doubt will, 
receive favorable consideration. In general, the fresh water fishes, 
when taken from cold water, have firmer flesh and are better flavored 
than those taken from warm water. In the northern lakes of the 
United States the temperature is seldom warmer than 60 F. Lake 
Amatitlan is 10 F. warmer. Owing to the fact that its volume of 
water is so great and its water so pure, it is probable that the Large- 
mouth Black Bass would not, to any marked degree, lose its good food 
qualities, and the Guapote would probably gain. There are several 
species of Catfishes which could easily be introduced at the same time. 

The best fishes to introduce into Lake Amatitlan are the Large- 
mouth Black Bass(Micropterus salmoides), the Rock Bass (Ambloplites 
rupestris), the Crappie (Pomoxis sparoides) , and the Bluegill (Lepomis 
pallidus). The second best fish seems to be the Guapote (Cichlasoma 
managuense) from the lakes of Nicaragua. The third choice would be 
the Mojarra (Cichlasoma motaguense) from Lake Isabel and the 
Montagua River. There could be no objection in introducing all of 
these fishes at the same time. 

The habits of the Moj arras" dre not well-known, and their recom- 



176 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

mended introduction into waters other than those in which they are 
now found is made with a little hesitancy. I am very sure that the 
introduction of those that I have named will do no harm, and the 
chances are that to introduce any or all of them will considerably 
increase the supply of food fish in the lake. 

If quantity of fishes or of fish food, at the expense of quality, is 
desired, the German Carp is recommended.* The Carp is a large, 
coarse fish which grows very rapidly. It is also very prolific. A 
female of 25 pounds' weight, brought to the Museum a few weeks ago, 
contained about 1,750,000 eggs. This fish is much cultivated in small 
ponds in Germany, Austria and other European countries, and for 
small ponds they are much desired, for they grow more rapidly than 
do most of our better food fishes. At one year old, they weigh about 
one pound. At three or four years of age, they grow in ponds to a 
weight of 6 to 8 pounds. In large bodies of water they grow even 
more rapidly. In the Fox River, near Chicago, Carp are often taken 
of over 30 pounds weight. In the Illinois River more pounds of 
Carp are taken by commercial fishermen than of all other fishes com- 
bined. The Carp feeds upon plants, and of this class of food there is 
an abundance in Lake Amatitlan. 

If Carp are introduced into the lake, it would not be so desirable 
to put into it the Large-mouth Black Bass, or the other fishes men- 
tioned. In eating vegetation the Carp digs up the bottom, much as 
do hogs. In this way they might destroy spawning places for Mojarras, 
Large-mouth Black Bass, and other fishes, and the areas suitable for 
spawning places for these fish are small. In addition to this, they are 
sure to become abundant enough to stir mud and sand around the 
shores to the extent of making the water very muddy. In this way, 
the Carp would partially destroy some of the beauty of the lake. 

In the introduction of the fishes mentioned the important thing 
to decide is whether first-class fishes are desired or not. If they are, 
the Carp should not be introduced into the lake. It is not nearly so 
good a food fish as is the Mojarra. If Carp are introduced, the supply 
of fishes for food will be many times as great as it is now, and perhaps 
twice as much as if the other species mentioned were introduced. The 
introduction of Carp is quite sure to decrease the abundance of better 
fishes, such as the Large-mouth Black Bass, the Crappie, the Rock 
Bass and the Guapote. For the introduction of any of the fishes 
mentioned, the food supply is abundant. The water is clear and pure, 
and the temperature is such that they would feed during the entire 
year, and thus grow rapidly. 

* Mr. J. W. Ticomb strongly believes German Carp should not be introduced into this lake. 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 



177 



In order that fishes should exist in at least fairly large numbers, 
they should not be disturbed during the breeding season. The supply 
of fishes in Lake Amatitlan is much reduced in numbers by over fishing 
during the breeding season. Especially is this true of the Mojarras. 
This fish deposits its eggs in nests made by it in the sand at the base 
of the Tules. When depositing their eggs, the fishes are very persistent 




FISHERMEN, LAKE AMATITLAN 

in remaining in shallow water along the shore, and so at that time they 
are more easily caught. In catching them by the methods used by 
the lake fishermen many of the nests are destroyed, and the chances 
for increase are much reduced. During the breeding time of food 
fishes a portion or all of their spawning grounds should be protected. 
The fishes at the breeding time are not so good to eat as at other times 
of the year. Another bad feature in the taking of Mojarras is the 
capture of such a large number of small individuals. The smaller 



178 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

ones should not be taken from the lake. In one or two years they 
would grow into large fish and be more desirable. The German Carp 
is about the only species of fish that will increase rapidly no matter 
when, or where, or how caught. All other species should be protected 
and cared for during the breeding season ; and the small ones, those less 
than X or % grown, should not be taken from the lake, but if caught 
should be returned immediately to the water. The spawning time of 
the Mojarras and the Large-mouth Black Bass is in the spring the 
most of it during April, May, and June. If the laws regarding fishing 
in Lake Amatitlan were as strict as they are in the lakes of Illinois, 
Indiana, and others, of our northern states, the Mojarras there would 
greatly increase in numbers. The Carp need no protection, and where 
the volume of water is as great as it is in Lake Amatitlan, they are 
quite sure, if introduced, to always be plentiful. Personally, I should 
advise that Carp be not introduced into the lake. 

During a portion of January and February a maximum and mini- 
mum self-registering thermometer was exposed at Laguna with the 
following results. The coldest time of the day was between 3 and 
5 A. M. The warmest was between 2 and 4 p. M. 

January 17, coldest 66 F. warmest 75 F. 

18, " 65 " " 76 " 

19, " 65 " " 76 " 
" so, " 61 " 74 " 

21, " 60 " " 74 " 

22, " 62 " " 79 " 

23, " 56 " " 70 " 

24, " 56 " " 67 " 
" 25, " 55 " " 66" 

26, 55 ' 64 " 

27, " 56 " " 66 " 

28, " 53 " " 65" 

30, " 58 " " 69 " 

31, " 61 " " 69 " 
February i, " 59 " 72 " 



LAKE ATITLAN. 

Lake Atitlan is a mountain lake, whose elevation is about 5,000 
feet above the sea. Except for the narrow pass to the south, through 
which one passes on the road between San Lucas and Patulul, the 
lake is surrounded by mountains, which rise directly from the water's 
edge to an elevation of about 2,500 feet above its surface. There are 
several small streams flowing into the lake. The largest one empties 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 



179 



into the lake near the village of Jairal; the next largest near Pana- 
jachel. The valleys drained by these streams are each about one mile 
wide and two or three miles in length. So small are all of these valleys 
that the shore of the lake has been but very slightly changed since its 
formation. The lake has no visible outlet. If it ever had one it was 
through the San Lucas pass. On the south shore of the lake are two 
volcanoes, Atitlan and San Pedro, whose summits are 7,000 feet above 




LAKE ATITLAN SHOWING DEPTH WHERE SOUNDINGS WERE TAKEN 

the lake and 12,000 feet above the level of the sea. To the north and 
back of the mountains bordering this side of the lake, is the plateau 
over which the upland road between Guatemala City and Quezaltan- 
ango passes. This plateau is about 5,000 feet above the lake. 

Lake Atitlan is about 12 miles wide and about 24 miles in length. 
It is one of the most beautiful of our American lakes, and is situated 
in a most delightful and healthful climate. Its elevation, and the 
scarcity of lowland and swampy places, unfit it as a habitation for 
mosquitoes, and so it is always free from malarial fevers. 



180 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

Along the greater part of the shore line the mountains rise perpen- 
dicularly out of the water, and so within a few feet of the water's edge 
the depth is very great. At almost any point along the shore from 
San Lucas to Santa Cruz (the only shore where soundings were made 
near the water's edge) the lake less than X mile from shore is between 
400 and 700 feet in depth; near the middle of the eastern half of the 
lake its depth is over i ,000 feet. The deepest place found by me was 
1,055 feet, which is probably the deepest place in the lake. ' 

The water in the lake is exceedingly clear. A white disc 12 inches 
in diameter can easily be seen at a depth of 45 feet. The shallow 
water near the shore is confined to the small stretches at the mouth 
of the few small inlets, and to the shore to the north of Atitlan and 
west of San Lucas. The margins of these areas usually support a 
growth of Tules such as are found in Lake Amatitlan. In these 
limited areas, water plants, as Chara, Potamogeton, and Algce, are 
abundant. 

Of microscopical animal and plant life there is less to a cubic foot 
of water in Lake Atitlan than in Amatitlan. As compared with its 
immense volume of water the shore vegetation is very small and 
the spawning and feeding grounds for fishes are very much re- 
duced. 

The temperature of the water in Atitlan is 68 degrees. The surface 
during warm days becomes slightly warmer to a depth of about 5 feet. 
Below 5 or 10 feet the temperature of the water in the lake is 68 F. 
I was unable to take the temperature deeper than 750 feet, but wher- 
ever taken the temperature was the same. There are two small 
streams flowing into the lake near Panajachel. Between 3 130 and 
5:30 P.M. on February 19, the temperature of the water in both of 
these streams near the lake was 64 F. 

In Lake Atitlan there are but three species of fishes, all of which 
are natives of Lake Amatitlan. The largest is the Serica (Cichlasoma 
nigrofasciatum) ; the most abundant is the Pescadito (Poecilia 
sphenops) , and by far the least important is the Gulumina (Fundulus 
guatemalensis) . These fishes are much used for food by the natives, 
especially by those people living in Santa Catalina. These fishes are 
eaten only because no others are to be had. An effort is being made 
to introduce into this lake fishes from the rivers of the lowland. 
Already two or three species of Mojarra and the Pepemechin have 
been brought up from the lowlands and placed in a pond near San 
Lucas. It is very doubtful if much benefit will be derived from this 
effort to stock the lake, but certainly no harm can result from it. 
The same energy, more wisely applied, might result in more good. 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 181 

This effort is an experiment, with chances in favor of increasing and 
improving, to a very limited extent, the fishes in the lake. 

The conditions for introduction of fishes into Atitlan are much 
different from those existing in Lake Amatitlan. Atitlan is very deep, 
with but a small amount of shallow water for spawning and feeding 
grounds. It is very certain that Lake Atitlan cannot support nearly 
so many fishes per cubic meter of water as can Lake Amatitlan. Its 
volume of water being many times greater, the capture of the fishes 
would be much more difficult. The stocking of this lake for strictly 
commercial purposes is sure to result in disppointment. 




LAKE ATITLAN NEAR PANAJACHEL 

The fact that Lake Atitlan is such a beautiful sheet of water, situ- 
ated at an altitude, and so completely surrounded by mountains as to 
insure it a delightful and healthful climate, is quite sure to cause it to 
become a resort for many people living in the cities and in the lowlands 
of Guatemala. There is nothing that would add more to the attrac- 
tiveness of this place than to have in the lake a fair supply of first-class 
game fishes, that is, fishes whose capture with hook and line would 
afford recreation and pleasure. Fishes of this sort, which are common- 
ly known as game fishes, are the only ones that should be introduced in- 
to this lake. Of all fishes the Carp should be avoided. The vegetation 
about the lake is too scant to ever enable this fish to become abundant 



182 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

enough to be of commercial value. The difficulty of taking it, or any 
large fishes, from the lake with nets would be so great as to make fishing 
for them for commercial purposes unprofitable. 

The water in Lake Atitlan is cool enough and pure enough to 
justify the introduction of Rainbow Trout (Salmo irideus). This is a 
very beautiful fish, a very excellent food fish, and one very popular 
with the professional sportsman who fishes for pleasure with hook 
and line. It is one of the very best American game fishes. This fish 
grows to a weight of 10 to 12 pounds in comparatively warm water, 
the average weight being from 3 to 6 pounds. In very cool water the 
growth is slow, and the fishes may never exceed one or two pounds in 
weight. The introduction of the Rainbow Trout is very simple and 
easy, if care is taken. The eggs can be obtained at hatching stations 
operated by the United States Bureau of Fisheries, packed in ice and 
shipped to the lake, and there hatched. After trout eggs have been 
hatched until the eyes appear as dark spots, their development can 
be arrested by packing them in moss on trays which are surrounded 
by ice. Eggs packed in this way have been sent to Europe, Argen- 
tina, South America, and to New Zealand, and they could easily be 
taken in this way to Lake Atitlan. The small streams which flow 
into the lake would furnish a limited spawning area, but the supply of 
fishes could easily be increased by the addition of a small hatching sta- 
tion on one of the streams. The artificial propagation of trout 
presents no serious difficulties. Any intelligent person who is careful 
can, with a little training, successfully operate one of these stations. 
The Rainbow Trout is a fish which quite readily adapts itself to sur- 
rounding conditions. Its natural habitat is in water cooler than that 
found in Lake Atitlan. It is known to live in water as warm as 75 F. 
and it is very certain that it will do well in a large body of pure water, 
such as we find in the lake in question. 

In addition to the introduction of Rainbow Trout, the Steelhead 
Trout (Salmo gairdneri) and the Landlocked Salmon (Salmo 
sebago) are recommended. These fishes grow larger than do the 
Rainbow Trout, and their eggs can be transported and hatched ,in 
the same way. The Trout and Salmon are much more easily intro- 
duced into the lake than are any others, and they are far more de- 
sirable. 

The next desirable fishes to introduce into Lake Atitlan are the 
Large-mouth Black Bass, the Rock Bass and the Crappie. These 
fishes would probably do well in the lake, but they should not be 
introduced if any or all of the species mentioned above are put into the 
lake. No species of fishes will ever become abundant in this body of 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 183 

water, because the spawning and feeding grounds are so small, when 
compared with the immense volume of water in the lake. 

Lake Atitlan will always be attractive to the pleasure seeker, if 
it contains game fishes like the Rainbow Trout or the Large-mouth 
Black Bass. The money brought to its shores by the pleasure-seeker 
will, no doubt, be greater than could be realized from the capture and 
sale of German Carp if introduced there, for this lake is not suited for 
Carp, and its introduction into this lake should not be considered. 
The food supply is not at all large, and the great depth of the water 
would render the capture of the Carp very difficult. Carp should 
never be introduced into Lake Atitlan. 

The Rainbow Trout, the Steelhead, and the Landlocked Salmon 
are the most favored fish for this lake. If these fishes are not selected, 
the next best are the Large-mouth Black Bass, the Crappie, the Rock 
Bass, and the Bluegill. 



THE FISHES OF LAKES AMATITLAN AND ATITLAN. 

The fish fauna of these lakes is not extensive. In Lake Amatitlan 
occur seven species, only three of which, the smallest ones, are found 
in Lake Atitlan. Of those in Lake Amatitlan only three exceed a 
length of four or five inches, and two of these are very slender, which 
really leaves but one species which, if in the United States, would be 
considered of sufficient size to become a marketable fish. This largest 
species is not plentiful, due largely no doubt, to over fishing. For 
catching the smaller species, the ordinary cast or throw net is used. 
These nets vary in size from about four feet to about ten feet in diam- 
eter. The mesh is about l / 2 inch stretch measure. The larger 
Mojarras are taken with gill nets, which are usually about six feet in 
depth and about 100 to 300 feet in length, with a mesh of about 1^4 
inches, stretch measure. 



Family Siluridse. CATFISHES; B ACRES; JUILINS. 

Rhamdia cabrerae Meek. JUILIN. 

This fish inhabits the lake, though it is more abundant in the 
outlet. Its food consists almost entirely of insects and insect 
larvae. The stomachs of most of those examined by me con- 
tained almost entirely the larvae of the mosquito and the damsel 
fly. The Juilin seldom reaches a length of over 200 mm. It is 



184 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

very slender, and so one that is full grown is not large. As a fish 
for food for man, or for food for other fishes, it is of very little 
importance. It is reported to spawn during the months of March, 
April and May. Lake Amatitlan, scarce. 



Family <> ninot i<la>. EELS. 

Qymnotus carapo Linnaeus. ANGUILLA. 

This fish reaches a length of about 210 mm. It is very 
slender. During my stay at the lake I saw but three specimens 
of this species, and was unable to learn much about its habits. 
I was told that it is only occasionally taken in the lake, and though 
it is much prized as a food fish, it is too small, and found in too 
few numbers, to be of any economic value. This fish inhabits 
streams from Lake Amatitlan and Rio Motagua to the Rio de la 
Plata in South America. Lake Amatitlan, scarce. 



Family Characinidse. CHARACINS. 

Astyanax micropthalmus Gunther. PEPESCA. 

This fish reaches a length of about 140 mm. It is a deep fish 
of silvery color, with a dark band on the posterior half of the middle 
of the body. The food of this fish consists almost wholly of 
insects and insect larvae. These fishes usually go to deep water 
in the daytime and so seldom are fished for except at night. They 
are most abundant in the inlets and near the outlet of the lake. 
The Pepescas are sold in large numbers in the markets at Ama- 
titlan. They spawn about May, probably April, May and 
June. I could secure no information in regard to their spawning 
habits. This fish is too small, and is found in quantities not large 
enough to be of much economic value. Lake Amatitlan, common. 



Family Pceciliidse. KILLIFISHES. 

Fundulus guatemalensis Gunther. GULUMINA. 

The Gulumina is a small, nearly cylindrical fish which grows 
to a length of about 85 mm. It is more abundant in the outlet 
of the lake than in the lake itself. This fish is seldom taken in 
shallow water along the shores where the Pescaditos are most 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 185 




FISH TRAP LAKE AMATITLAN 




FISH TRAP, LAKE AMATITLAN 



186 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

abundant. I examined many large catches of the latter and did 
not find in them a single species of Gulumina. I observed this 
small fish to be exceedingly abundant along the railroad fill. 
During warm days, when the sun was shining brightly, they would 
rise in large schools near the surface of the water. On coming 
near the water's edge, or approaching them slowly in a boat, they 
would sink to a considerable depth and hide among the rocks. The 
food of this fish consists almost entirely of insects and insect 
larvae. It is said to spawn about March and April. Lakes Amati- 
tlan and Atitlan, scarce. 

Pcecilia sphenops C. & V. PESCADITO. 

There are probably more individuals of this fish in Lake 
Amatitlan than of all other fishes combined. It is a small fish, 
in shape and size much like the Gulumina. This fish is vivi- 
parous; that is, it brings forth its young alive. Each female has 
a brood of from 30 to 50 small fishes. The young are born in 
March and April and May. This fish feeds on filamentous alga?, 
the larger species of free algae, and the tender parts of the Char a, 
Potamogeton and Ceratophyllum. They also eat mud in which 
microscopic animal and plant life is abundant, and also insects and 
insect larvae when these are abundant. This species comes near 
shore in greater numbers during the night, yet they seem very 
plentiful in daytime in shallow water. They are caught in large 
quantities by the residents of this region. Their flesh is quite 
firm and well flavored, but the many small bones and their small 
size prevent them from being very desirable for food. The 
absence of better fish, or the presence of no fish at all, and the 
ease with which they can be taken in large numbers, largely 
explains why so many are used for food by residents about the 
lakes. These fishes are captured by the small-mesh throw-nets 
used so extensively in Spanish American countries. In order to 
make their capture more certain and easy, the fishermen build 
nearly circular basins along the margins of the lake. These 
basins are formed by placing rocks around the margin, enclosing 
areas of shallow water usually about one or two feet deep and 
from 5 to 15 or 20 feet in diameter. These are often built in the 
shade of an overhanging bush, or they may or may not be covered 
with brush. On the side towards the lake a narrow opening is 
left through which these small fishes enter the basin. In a short 
time the Pescaditos enter these basins in large numbers. After 



APRIL. 1908. LAKES AMATITLAN AND ATITLAN MEEK. 187 




FISH RUNWAYS, SANTA CATARINA. LAKE ATITLAN 




CATCHING SERICAS LAKE ATITLAN 



i88 FIELD COLUMBIAN MUSEUM ZOOLOGY. VOL. VII. 

they have become accustomed to these places, the fisherman 
removes the brush and the fish continue to enter the enclosure the 
same as before. When the net is thrown into the center of the 
enclosure, the fish become frightened and swim in all directions. 
By the time the net strikes the water they have gone to the edges 
of the basin, and not being able to escape swim back towards the 
opposite side and thus many are caught under the net. A few 
throws take most of the fish out of the basin. Soon, however, 
others come in and are captured in the same way. The Pesca- 
ditos frequent the shore and these basins in larger numbers at 
night than in the daytime, and so fishing for them is done mostly 
after sundown. In rocky places, and where there is no shallow 
water, these basins are made by digging back in the shore, and some 
have been made at the expense of considerable labor. These 
small fishes are usually more abundant along the shores where 
there are warm springs. On Lake Atitlan, at Santa Catarina, is 
a stretch of shore line where there is considerable surface of warm 
water. At this place narrow trenches are dug back some dis- 
tance, which this species frequents in large numbers, where they 
are easily caught. The shore of this lake contains only small 
areas of shallow water, and does not afford opportunities for the 
construction of small trap-like basins for the capture of this fish, 
as does the shore at Lake Amatitlan. Conical traps, made of 
wickerwork, are also used here to capture these fishes. The 
Serica is, however, more easily taken in these traps than is this 
species. In these lakes and neighboring waters there are evi- 
dently more individuals of the Pescadito than of all other fishes 
combined. This is especially true of Lake Atitlan. This species 
is very abundant in fresh and brackish water of the lowlands of 
southern Mexico, south to Nicaragua. In Central America it is 
the small fish found near the head waters of rivers on both sides 
of the divide. It is the small fish usually seen swimming near 
the hot springs in Middle America. It probably never goes in 
water warmer than 100 to 110 F. It certainly does not at 
Amatitlan. As food for game fishes, it will serve its purpose best. 
The introduction of a fish which lives on small fishes is the best 
means of converting this species into much better food than 
it at present makes. Lakes Amatitlan and Atitlan, very 
abundant. 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 189 

Family Cichlidse. MOJARRAS. 

Cichlasoma nigrofasciatum Giinther. SERICA. 

Next to the Pescadito, the Serica is most abundant in the 
lakes. It is a small Mojarra never growing longer than 100 mm. 
As a food fish it is considered of little value by the people who live 
on Lake Amatitlan. The chief objection to it is its small size and 
the numerous small bones it contains. This fish is not seen in the 
markets and seldom in the catch of any of the fishermen there. 
It is very abundant along the shores where there is much vegeta- 
tion, as it feeds almost entirely on algae and the tender parts of 
the higher water plants in the lakes. It is a handsome, active 
fish, but of no important commercial value. This fish in Lake 
Atitlan is of more importance, due largely to the absence of larger 
fishes. It is easily captured by use of conical wickerwork traps, 
which are set in the water where vegetation is abundant. The 
Serica will enter fish traps of this style in Lake Amatitlan in far 
greater numbers than do any of the other species there. Its habits, 
so far as known, are about the same as those of the Mojarra. They 
deposit their eggs in April, May and June. So far as known, this 
fish is found only in the mountain lakes of western Guatemala, 
but it is not, at present, recorded from any of the rivers of the 
Republic. Lakes Amatitlan and Atitlan, abundant. 

Cichlasoma guttulatum Giinther. MOJARRA. 

This is the largest fish in Lake Amatitlan. The largest speci- 
men obtained by me was 270 mm. in length. It is a very hand- 
some fish ; its flesh is well flavored and very firm. As a food fish 
it is regarded as one of the very best in the fresh waters of the 
republic. This fish feeds to some extent on small fishes, but 
plants formed much the largest supply of the food of a large 
number of specimens examined by me. The Mojarra deposits 
its eggs in nests made in the sand and gravel in shallow water at 
the base of the Tules. I am told that they deposit their eggs in 
April, May and June. This fish is found in the rivers on the west 
slope of Guatemala. Its rather small size, and being found in 
rather small numbers, prevent its becoming a food fish of much 
importance. Over fishing, especially during the breeding season, 
is always sure to keep the numbers of this fish much reduced in 
the lake. All of the individuals of the species which are caught, 
whether large or small, are used for food. These fishes are 



igo FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

usually taken in gill nets. These nets are about one to 300 feet 
in length and about 6 feet in depth. A net is run out for about 
^3 of its length along the edge of the Tules ; the ends are carried 
at right angles into the Tules, forming three sides of a rectangular 
enclosure. The fishermen then get between the shore and the 
net, and drive the fishes with considerable vigor towards the net. 
They appear to be easily gilled. The net is then taken up and 
put out as a seine into the deeper water just outside the line of the 
Tules, in the form of a circle. The boat is anchored to the Tules, 




FISHING FOR MOJARRAS, LAKE AMATITLAN 

the ends of the net are drawn to the boat, and the circle closed by 
lapping the ends of the net. The fishermen slowly pull in the net 
by the cork line, permitting it to gather in folds at each end of the 
boat. Usually several fishes are gilled in this way, and are taken 
out as the net is pulled in. The fishermen then move to another 
place and repeat these hauls till a sufficient number of fishes are 
taken. This species of fish is usually taken in daytime. It is said 
that at night they go into deep water. The largest numbers are 
taken during the months when they are breeding, for during this 
time they are more easily caught. The practices of the fishermen 
on Lake Amatitlan in taking this fish at all times of the year are 
very harmful to their own interests, and would not be tolerated on 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 191 

any lake or stream in the United States. These fish should not be 
disturbed when they are depositing their eggs, and at other times 
of the year only the larger ones captured should be retained, and 
all others returned to the lake. Lake Amatitlan, common. 



AMPHIBIANS OF LAKES AMATITLAN AND ATITLAN. 

One toad and three frogs are the only Amphibians taken at 
these lakes. During the winter and the dry season these animals 
are not abundant in the tropics, and the following list is not a fair 
index of their abundance in these places. The larger frog, Rana 
pipiens, is the only one used for food by the natives. It occurs 
at both lakes. For assistance in the identification of these species 
I am indebted to Dr. L. Stejneger, Smithsonian Institution, 
Washington, D. C. 



Family Bufonidae. TOADS; SAPOS. 

Bufo marinus Linnaeus. TOAD; SAPO. 

Several toads inhabit Guatemala, but this is the only species 
I found on the shores of Lake Amatitlan. This species deposits 
its eggs in shallow water, and there they develop into the larval 
or tadpole stage. In this stage they feed chiefly on algae. Al- 
though many of them are eaten by fishes they are not abundant 
enough to furnish any large supply of food for fishes. This toad 
is very abundant in the West Indies, and from southern Mexico 
to Brazil. It is one of the largest toads in Middle America. 
Abundant on shores of Lake Amatitlan, but it does not occur at 
Lake Atitlan. 



Family Ranicke. FROGS; RANAS. 

Rana pipiens Gmelin. FROGS; RANA. 

This is the larger of the two frogs found in this region. It is 
found in wet places and in shallow water, along the shores of 
both lakes. Its feet are webbed, a character which distinguishes 
it from the species listed below. It deposits its eggs in shallow 



192 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

water, and these develop into a larval or tadpole form, which much 
resembles that of toads, and which has similar habits. The tadpole 
or larval form of the frog is larger than that of the toad, though 
the adult is smaller. Lakes Amatitlan and Atitlan, common. 



Family Cystignathidse. FROGS; RANAS. 

Leptodactylus microtis Cope. FROG; RAN A. 

This small frog is quite abundant in wet places under stones, 
pieces of wood or other material, which easily conceal them. 
Its breeding habits are the same as those of the preceding species. 
Though quite abundant about the shores of the lake Amatitlan 
it is too small to be of much economic importance. The adult 
frog and the adult toad feed mostly on insects. This species was 
not taken at Lake Atitlan. Common at Lake Amatitlan. 



THE REPTILES OF LAKES AMATITLAN AND ATITLAN 

Reptiles were not abundant during January and February on 
or about the shores of these lakes, and none of those found there, 
except one turtle, are distinctively water animals. The following 
list comprises all that were taken or were common near the water's 
edge. No water snakes, or rather snakes frequenting the water, 
were observed during my stay at these lakes. 



Family Iguaiiidre. IGUANAN. 

Basaliscus vittatus Gray. 

A few specimens of this species were taken along the more 
rocky shores of Lake Amatitlan. It is not nearly so abundant 
here as in the lower lands. 

Iguana rhinopla Gray. IGUANA. 

One specimen was taken during my stay at Lake Amatitlan, 
the only one I saw. 

Ctenosaura acanthura Gray. IGUANA. 

This species is very abundant along the rocky shores of the 
lake. Its eggs and flesh are eaten by the natives. This species 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 193 

and the two preceding apparently do not occur on the shores of 
Lake Atitlan. This lizard is very abundant along streams in the 
lower lands of western Guatemala. 



Family Teiidse. 

Ameiva undulata Gray. 

This small lizard is quite plentiful on the shores of both of 
these lakes. It seldom, if ever, enters the water, and is too small 
to be of any economic value. 



Family Cinosteridse. TURTLES. 

Cinosternum cruentatum Dumeril. TURTLE; TORTUGA. 

The only turtle I saw at Lake Amatitlan was an individual of 
this species which I purchased of a native at Laguna. So far as 
I could learn, turtles are very scarce in this region. The specimen 
here listed agrees well with the accounts of the species as given by 
Dr. Gtinther and Dr. Boulenger. Length of carapace 122 mm., 
width, 85 mm., depth, 62 mm. ; length of anterior lobe of plastron 
42 mm., of middle lobe 27 mm., of posterior lobe 45 mm.; pos- 
terior margin of plastron with a slight notch. 

The members of the family to which this species belongs are 
regarded as inferior for food. The introduction of one or more 
turtles would increase the food supply of the lake, and in no way 
be harmful to the fishes now there, or to the fishes introduced. 



THE WATER BIRDS OF LAKES AMATITLAN AND ATITLAN. 

The following list of water birds includes only such species as 
were collected, by Mr. Barber or by Dr. Dearborn, or positively 
identified by other means, during a brief visit to these lakes in 
March and April, 1906. It may be well to state in this connection 
that both of these lakes are centers for all bird life, at least during 
the dry season, when the surrounding mountains are without 
green vegetation, and the short alluvial valleys alone furnish 
green foliage and food for all classes of birds. Most of the species 
here named are undoubtedly to be found in this region only in 



iQ4 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

winter, as their breeding range is much to the northward of 
Guatemala. This account of the water birds of this region was 
kindly furnished me by Dr. Ned Dearborn* of this museum. 



Family Podieipedidse. GREBES. 

Colymbus dominicus brachypterus Chapman. SHORT-WINGED 
GREBE. 

A small colony of Short-winged Grebes frequented an area of 
surface vegetation in a small bay of Atitlan near Panajachel, 
whence several specimens were collected in April. 

Colymbus nigricollis californicus Heermann. AMERICAN EARED 
GREBE. 

American Eared Grebes were found in small numbers at the 
western end of Amatitlan, and more common and generally dis- 
tributed near Panajachel on Atitlan. At this latter place, the 
Indians, by dextrous paddling in small canoes, tire out and 
capture these Grebes after a short but lively chase. The Grebes, 
as well as all the other species of water birds, remain near the 
shore -when undisturbed, as the rapidly declining bottom of the 
lakes allows them only a narrow margin to feed upon. 



Family Aiiatidse. DUCKS. 

Querquedula discors Linnaeus. BLUE-WINGED TEAL. 

One specimen of Blue-winged Teal, taken on Atitlan by Mr. 
Barber in February, was the only duck encountered that could be 
identified. A flock of several hundred ducks was seen at Ama- 
titlan, but they were so wild that it was impossible to approach 
near enough to make out what they were. The same uncertainly 
prevailed with regard to a few other ducks at Atitlan. 



Family Ardeidse. HERONS. 

Butorides virescens Linnaeus. GREEN HERON. 

Green Herons were found scatteringly in all parts of the 

*For an account of the birds collected on this Expedition, see Publica- 
tion 125 Field Mus. Nat. Hist., Ornithological Series, Vol. i, No. 3, 69 to 138, 
1907. 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 195 

Republic that were visited. In the collection made by Mr. 
Barber at Atitlan is one specimen. 



Family Kallida'. RAILS; COOTS. 

Porzana Carolina Linnaeus. CAROLINA RAIL. 

Carolina Rails winter sparingly about the shores of both these 
lakes, specimens being taken at each of them. They follow the 
fringe of tules wherein are food and seclusion. 

(iallinule galeata Lichtenstein. FLORIDA GALLINULE. 

A single Florida Gallinule, the only one observed, was taken 
at Amatitlan in February. It was living in a patch of tules 
adjacent to a hot spring. 

Fulica americana Gmelin. COOT. 

Coots winter abundantly at both lakes. They procure most 
of their food by diving, a short distance out from shore, though 
they feed more or less in the strip of tules that fringes the water's 
edge. They dive without difficulty, notwithstanding the fact 
that when they come to the surface to breathe and swallow, they 
come up as buoyantly as pieces of cork. Coots are captured by 
the native boatmen at Atitlan in the same manner as Grebes are, 
that is to say, by running down, when a blow from a paddle 
quickly ends the chase. This mode of pursuit was observed 
frequently at Atitlan by both Dr. Meek and Mr. Barber, but at 
Amatitlan the gun was the only weapon used against any sort of 
water- fowl. 



Family Scolopacidxe. SNIPES. 

Gallinago delicata Ord. WILSON'S SNIPE. 

Several Wilson's Snipe were seen at Atitlan in March by Mr. 
Barber. 

Acititis macularius Linnaeus. SPOTTED SANDPIPERS. 

A few Spotted Sandpipers winter in this region. One was 
seen at Amatitlan and two were secured at Atitlan. 



196 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

Family Charadriidse. PLOVERS. 

Oxyechus vociferus Linnaeus. KILLDEER. 

The Killdeer winters in some parts of Guatemala notably 
along the Motagua River in considerable numbers. One was 
observed at Atitlan on April gth. 

Family Alcedinidse. KINGFISHERS. 

Ceryle alcyon Linnaeus. BELTED KINGFISHER. 

Belted Kingfishers were not uncommon at Atitlan, where 
several were seen and one taken. One was seen at Amatitlan. 

Ceryle americana septentrional is Sharpe. TEXAS KINGFISHER. 

Texas Kingfishers were found at both lakes, but more com- 
monly at Atitlan, where two specimens were secured. 



THE ZOOPLANKTON OF LAKES AMATITLAN AND ATITLAN. 

The lowest forms of microscopic animals found in these lakes 
are treated under this head. They do not occur in any very 
great abundance and the number of species is small. The follow- 
ing account of these forms was kindly furnished me by Mr. H. 
Walton Clark, Assistant, U. S. Bureau of Fisheries, Washington, 
D. C. 



Family Volvocidse. 

Ccelastrum microporum Naegeli. 

Not uncommon. A few specimens were found scattered 
through samples No. 19 (Feb. 5th, Amatitlan, towing made at noon 
from bottom to top in no feet water) and No. 20 (Jan. iyth, Lake 
Amatitlan, in front of hotel). None of the specimens showed 
the tubercles on the cells shown in many illustrations, but accord- 
ing to descriptions and a few figures, these may be absent. One 
colony appeared to possess eye-spots, one in each cell. One colony 
examined measured 60 //. diameter, cells 15 ,; full grown col- 



APRIL, 1908. LAKE AMATITLAN AND ATITLAN MEEK. 197 

onies are said to attain a diameter of 40-100 /.*., and individual 
cells as much as 25 /*. 

Eudorina stagnate Wolle. 

This is one of the common elements of the plankton, occurring 
in the greater number of samples, never in great abundance, but 
usually several, and often numerous examples could be seen in the 
field at the same time. It was quite frequently found in stages 
of active division. 

I have not had opportunity to compare carefully Wolle's 
description of Eudorina stagnate with the description of the 
European form, elegans Schmidle. In a recent article on Algae 
from Brazil, he identifies the Eudorina found there as elegans. 



Family Peridinidse. 

Peridinium tabulatum Ehrenberg. 

Common in most of the plankton, abundant in a good deal of it. 
The form at hand is that with the cleft anterior portion ; diameter 
of a specimen measured, 65 /*. Griffith and Henfrey give the 
length as 1-480", which reduces to 5 2 /*. All our examples appear 
to be of nearly uniform size. They are exceedingly abundant 
in sample 8, collected at the west end of Lake Amatitlan, on the 
surface. This catch consisted mostly of insect exuviae, and it 
is remarkable that the greater number of the Peridiniums were 
crowded densely in the cast-off skins, as if they had worked their 
way in for food or shelter. 

Peridinium hirundinella O. F. Muller. 

Rather common; scattered through most of the phyto- 
plankton from Lake Amatitlan, and also in the Atitlan material. 
Our specimens agree very well with the figures found in Kent, 
and in the figures in the Riverside Natural History. All are 
robust and quite rough. 

This species is almost cosmopolitan, having been reported 
from England, India (Kent), the Great Lakes (Riverside Nat. 
Hist.), and from lakes in Iceland (Ostenfold). (I have so far 
found none in Lake McDonald, Alaska, though there are several 
other species represented.) Apstein (1, c.) notes slender 3 -horned 
specimens as occurring in the Dorbesdorfer Sea. All the exam- 



igS FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

pies seen from Lake Atitlan were 4-horned, but many, perhaps 
the majority, from Lake Amatitlan, were 3 -horned. They did not 
appear to be more slender than the others, however. Kent gives 
the size as "Length 1-120" to i-9o"-2o8 , to 277 /->.." The 
examples at hand measured 220 /* long, and 70 , wide at the 
broadest portion of the body. 



SPONGE IN LAKE AMATITLAN. 



Family Spoiigilidfle. FRESH-WATER SPONGES. 

Spongilla fragilis Leidy. FRESH-WATER SPONGE. 

So far as I was able to discover, there is but one species of 
Fresh-water Sponge in Lake Amatitlan (none was observed in 
Lake Atitlan) . This sponge is not very abundant, and is usually 
found growing on rocks or pieces of wood in the water. It appears 
on these objects usually as light brown patches, although its color 
may vary from nearly white to a bright green. The shade of 
color depends much on the amount of light. The lighter shades 
are found in the darkest places, and the green color in bright sun- 
light. 

In general, this sponge bears some resemblance to our com- 
mercial sponges which grow in the sea. The important differ- 
ence between those in salt-water and fresh-water is in the com- 
position of the spicules the harder skeleton mass. The spicules 
of the salt-water forms are made up of a horny elastic fibre, while 
those of fresh water are composed of silica. 

The patches of sponges found on rocks along the shore of Lake 
Amatitlan are subcircular, being thin at the edges and thicker in 
the middle. 

This sponge is not abundant and is of no commercial value. 
It is apparently of no economic importance, so far as the fish 
supply of the lake is concerned. 

This species is very widely distributed over North America, 
but is not known from bodies of water farther south than Lake 
Amatitlan. For the identification of this species, I am indebted 
to Dr. Edward Potts, of Philadelphia. 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 199 

THE LEECHES OF LAKE AMATITLAN. 
By J. PERCY MOORE.* 

Family (wlossiphoniidee. SNAIL LEECHES. 

Glossophonia lineata (Verrill). 

This little leech was originally described from Nebraska and 
Florida. It is now known to range very extensively over the 
Pacific side of South America, through Central America, Mexico, 
the entire United States, and into the southern half of Canada, 
and is carried from place to place attached to the feet of migrating 
water birds. Several specimens were taken, in association 
with E. triannularis, under stones in Lake Amatitlan. 

Although presenting many varieties, a general characteristic 
of the species is the double line of small conical papilla along the 
middle of the back. The striking color pattern of brown and 
white in vivid contrast is also limited to this and one other species 
of the genus. 

Besides seeking concealment beneath stones and leaves in the 
water, it attaches itself to the bodies of snails, frogs and larger 
leeches, upon the first of which, as well as upon small worms and 
insects, it subsists. In common with other members of the 
genus it bears its eggs and young on the ventral surface, pro- 
tected by the inrolled margins, and supplied with currents of fresh 
water by the rythmic undulations of the body. When disturbed, 
it rolls into a ball and remains for a time quiescent. 



Family Erpobdellidje. WORM LEECHES. 

Erpobdella triannulata SP. NOV. 

Form moderately slender, width greatest at caudal end of 
clitelhim, thence nearly uniform, but tapering gently to caudal 
end; subterete in pre-clitellar region, moderately depressed, and 

*Two species of Leeches were found in Lake Amatitlan, but none was 
was taken in Lake Atitlan, as no special search was made for them there. 
These leeches are small, and one, or both, species is quite abundant under 
stones. The small size of these animals, and the fact that they are hidden, 
render them of little if any economic importance. The account here given 
of these leeches was prepared for this paper by Dr. J. Percy Moore, of the 
University of Pennsylvania. [S. E. M.] 



200 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

in cross-section elliptical in post-clitellar part; lateral margins 
rounded except near the caudal sucker, where thin lateral wings 
extend for a short distance. 

Mouth moderate, the upper lip rather short and broad and 
moderately furrowed. Eyes 3 pairs, the first much the largest 
and most conspicuous, situated in the dorsum of somite II, the 
other two pairs equal and situated one above the other at the sides 
of the mouth on somite IV. Clitellum thick, completely zonular, 
extending over 15 annuli (X b 5 to XIII b 4 inclusive), well defined 
and broader than contiguous segments. Genital orifices separated 
by three full annuli, the male being situated between the second and 
third rings of somite XI I (XII b 2 /a 2 ), the female at XII/XIII. On 
mature worms the male orifice is prominent, with rugose margins 
and elevated on a broad conical papilla. When the atrial chamber 
is everted this region appears as a slightly elliptical disk with the 
longer diameter transverse, with a slightly raised marginal rim, 
and near the center two small openings of the prostate horns. 
Completely quinque-annulate somites have all annuli of equal 
length, and not further subdivided except on much contracted 
specimens, which have all rings equally subdivided by transverse 
furrows across the middle. Anus large, with radical furrows sur- 
rounding it, situated 3 annuli in front of the anus. Posterior suck- 
er thin, flat, its diameter about two-thirds the greatest width 
of the body, marked on each side by several raised radiating 
lines. 

Color, yellowish olive or dull green, marked for the entire 
length with four longitudinal stripes composed of numerous small 
black spots with pale centers in which sensory papillae are situ- 
ated. The middle (paramedian) pair is usually the darker, and 
the supra-marginal duller and more diffuse, while the median 
light area is paler than those between the two pairs of dark stripes. 
Ventral surface and lateral margins plain gray or ashy and quite 
unpigmented. Other specimens have the dorsal pigmentation 
diffuse, giving an effect of dull brown or brownish black, the 
paramedian region being always deepest. In such specimens, 
the furrows are always pale, and the rings speckled with small 
white spots indicating the position of the sense organs. 

Atrium with median chamber relatively spacious, much as in 
Dina microstoma, not deeply bilobed nor much incised by the 
nerve cord ; prostate cornua small, curved laterally and downward 
to meet the vasa deferentia, which pass forward as long loops as 
far as ganglion XI. 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 201 

Length in moderately extended resting condition 25-30 mm., 
maximum width at posterior end of clitellum 3 mm., greatest 
depth nearly 2 mm. 

Egg-cases very flat, thin, yellowish, chitinoid capsules, ellip- 
tical, not produced at the ends, and with slightly developed thin 
margins; 3-4 . 5 mm. long and 2-3 mm. wide. They are attached 
by one face to the under-side of stones, sticks, etc., and each con- 
tains several eggs or young immersed in albumen. 

In the digestive tracts were found the remains of small insect 
larvae, oligochaete annelids, and other leeches, including their 
own species. 

Very abundant under rocks about the shores of Lake Amatit- 
lan, Guatemala, associated with Glossiphonia lineata (Verrill) 
Moore. I have also received specimens from other parts of Cen- 
tral America, Mexico, and the mountains of southern California. 

A small, slender leech, seldom exceeding 30 mm. in length, 
pale ashy below and of a yellowish olive or dull green color above, 
marked by two or four dusky longitudinal stripes, which may be 
diffuse and coalesced. On the head are three pairs of eyes, the first 
and largest on the upper lip, the other close together at the sides of 
the mouth. In addition to some features of the internal structure, 
this species is distinguished from related leeches by having all of 
the rings of the middle of the body of equal length and similar 
structure, and three complete rings intervening between the male 
and female external genital pores. 

It abounds about the shores of Lake Amatitlan, seeking con- 
cealment by day beneath stones and similar objects in the shallow 
waters, and at night becoming active in the pursuit of small 
worms, insect larvae, and even the smaller members of its own 
species, which constitute its chief food. Having no toothed jaws, 
it is not an habitual blood-sucker, though it doubtless, like related 
species, attacks abraded surfaces of higher animals when oppor- 
tunity offers. 

Not confined to Lake Amatitlan. It has been found through 
Central America, Mexico, and in the mountains of southern Cali- 
fornia, inhabiting streams as well as lakes and ponds. The eggs 
are deposited, several together, in a quantity of albuminous jelly, 
in small, very flat, elliptical, somewhat horny capsules, provided 
with a thin, often frilled border, and attached firmly to the under 
side of stones. 

Type No. 2389 Collection Academy of Natural Sciences of 
Philadelphia. 



202 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 
i 

CRUSTACEA OF LAKES AMATITLAN AND ATITLAN. 

Two species of larger Crustacea occur in Lake Amatitlan, but 
one of these, the Freshwater Crab, occurs in both lakes. During 
the breeding time for these species, they form a considerable 
amount of the food supply taken from Lake Amatitlan. 

For notes and the identification of these species I am indebted 
to Miss Mary J. Rathbun, of the Smithsonian Institution, Washing- 
ton, D. C. 

Family Palremoiiiila*. SHRIMPS: CAMARONS. 

Bithynis jamaicensis Herbst. CAMARON. 

The Camaron is a large shrimp which is quite abundant in the 
Pacific Coast streams of Middle America. It is now quite abun- 
dant in Lake Amatitlan, but is difficult to capture, except in April, 
May, and June during its breeding season. This species inhabits 
fresh waters from Lower California and Texas to Ecuador and 
Rio de Janeiro. It is also abundant in the West Indies, and 
wherever found it is much prized as an article of food. This large 
Shrimp or Camaron does not inhabit Lake Atitlan. The fact 
that it is abundant in the Pacific coast streams indicates that it 
is possibly native to Lake Amatitlan, although it is reported to 
have been introduced there. Lake Atitlan has no outlet, and it 
also has a very limited fish fauna, and so the absence of this 
crustacean might be expected. This Camaron is reported as 
abundant in the west coast rivers of Nicaragua, but is said not to 
occur in Lakes Managua and Nicaragua; but neither of these 
lakes communicates with the west coast streams. Except 
during the spring months, this species is said to go to deep water. 
At any rate they are seldom seen, or seldom captured, except 
during the breeding season. As an article of food, this Shrimp 
is very highly prized. Lake Amatitlan, abundant in breeding 
season. 

Family Potamonidse. CRABS; CANGREJOS. 

Potamocarcinus guatemalensis Rathbun. CAXGREJO. 

This crab is quite abundant in Lake Amatitlan, but like the 
Camaron is more easily captured during the breeding time, which 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 203 

is in February, March, and April. The eggs of this species are 
laid and then attached to the legs and caudal appendages, and 
are thus carried until the young are of sufficient size to care for 
themselves. The eggs and young of the Camaron are carried in 
the same way. To capture these animals when thus loaded with 
eggs or the young means much destruction to the species. The 
Cangrejo is much prized for food. Individuals when taken 
loaded with young should at once be returned to the water. If 
water animals are to become abundant and useful, the wholesale 
destruction of the young should be avoided. 

There are many species of fresh water crabs found in tropical 
waters, inhabiting streams, lakes, ditches and damp woods. 
Their food, like that of the Camaron, consists of insects and other 
small animals, and of water plants. Their abundance in Lake 
Amatitlan will depend largely upon the protection given them 
during the time they are taking care of their young. Lakes 
Amatitlan and Atitlan, common. 

The smaller Crustacea were comparatively more abundant 
in Lake Atitlan than in Lake Amatitlan. Many hauls were made 
with the tow net at or near the surface at nearly all hours of the 
day, and never, except once, were these forms taken in any con- 
siderable quantity. On February lyth, at about 4:30 P.M., I made 
a surface towing in Lake Atitlan, near San Lucas, with only 
average results. A second short haul, made about three-quarters of 
an hour later resulted in securing about a pint of these small forms. 
This haul was made just as it began to rain. It was evident to the 
naked eye that the surface of the water was alive with these 
small Crustacea. These forms were not observed to be at the 
surface in such numbers on several other evenings, about this 
same time, when examinations were made. 

The collections made at both Lakes Amatitlan and Atitlan 
were studied by Dr. E. A. Birge, Professor of Zoology of the 
University of Wisconsin, and by his assistant, Professor C. Juday. 
The following account of the Phyllopoda was prepared by Dr. E. A. 
Birge. 



Family Sididee. 

Diaphanosoma brachyurum (Lieven) G. O. Sars. 

A considerable number of females, not distinguishable from 
the North American representatives of this species, as found 



204 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

in the collections from Lakes Atitlan and Amatitlan. Length 
i.o mm.; height to 0.45 mm. 



Family Daplinithr. 

Daphnia pulex De Geer. 

By far the most abundant member of the Cladocera in the 
collection is a stout, semi-transparent representative of this 
species. The antennae are not very strong, and only slightly 
ciliated. The first and second abdominal processes are united 
at the base. There are 17-18 abdominal teeth. The distal 
pecten bears 6-8 teeth, of which the proximal is smaller than the 
others. The proximal pecten has about 10 small teeth. Length 
to 2 . 5 mm. ; height to i . 6 mm. Lakes Atitlan and Amatitlan. 

Oaphnia longispina O. F. Muller. 

A single specimen of this species was found in the collections 
from Lake Amatitlan. It is of the variety galeata Sars, and is 
not far from the form figured in Lilljeborg's Cladocera Sued, 
PI. XVII, fig. 9. Length 1.56 mm., including spine 0.4 mm. 
long; height 0.53 mm. 

Ceriodaphnia rigaudi Richard. 

Four immature specimens of this species were found in the 
collection from Lake Amatitlan. They included both varieties, 
three having one horn, and one specimen having two horns on the 
head. Length 0.4 mm. 



Family Itosini imhr. 

Bosmina obtusirostris G. O. Sars. 

A few specimens indistinguishable from this species were 
found in both lakes. Length 0.42 mm. 



Family Lynceidse. 

Alona, sp. 

Two immature specimens of a species of this genus were 
found in the collection from Lake Atitlan. Length o . 3 mm. 



APRIL, 1908. LAKES AMATITLAN AND ATITLAN MEEK. 205 

The following account of the Copepoda was prepared by 
Professor Chauncy Juday, of the University of Wisconsin. 

In the Plankton collection, from Lakes Atitlan and Amatitlan, 
the Copepoda are represented by only two forms. 



Family Centropagidae. 

Diaptomus albuquerquensis Herrick. 

Four specimens of this species were found in the material 
from Lake Atitlan, and four in that from Lake Amatitlan. Length 
1.4 to 1.7 mm. This form has been reported from Colorado, 
New Mexico, and the City of Mexico. 



Family Cyclopidre. 

Cyclops oithnoides Sars. 

A few adults were found in the collection from Lake Atitlan. 
Length o . 5 mm. A considerable number of immature specimens, 
which probably belong to this species, was found in the collec- 
tions from both lakes. 



SHELLS OF LAKE AMATITLAN. 

With the exception of one species, Sph&romelania largillierti, 
shells are not abundant about the shores of the lake. No bivalves 
were taken, and probably none exists there. My stay at Lake 
Atitlan was short, and no shells were collected there. The few 
unsuccessful searches made for these indicate that shells are not 
abundant on the shores of this lake. 

For the identification of these shells I am indebted to Dr. 
Ball and to Dr. Bartsch, of the Smithsonian Institution. 



Family llelanideB. 

Sphieromelania largillierti Phil. 

This is the largest and by far the most abundant species of 
shell found in the lake. It is found everywhere along the shore 



206 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. VII. 

on plants and rocks. This species deposits its eggs in January 
and February. The eggs are very large and are usually attached 
to the under side of rocks. This species is so abundant that its 
large gelatin-like eggs would furnish a considerable amount of 
food for small fishes. It is a very abundant species in Guatemala 
and San Salvador to Central Nicaragua. 



Family Amnicolidse. 

Amnicola guatemalensis Fisch & Crosse. 

A very small species and very scarce. Of no economic import- 
ance. 

Amnicola petensis Morelet. 

Very small and very scarce. Of no value. 



Family Limmeida*. 

Ancylus excentricus Morelet. 

Very small and very scarce. It is found attached to rocks. 

Planorbis subpronus Von Martens. 

Very small, rather common. Of no economic importance. 



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